IMDEA Water Institute, Avenida Punto Com, 2, 28805, Alcalá de Henares, Madrid, Spain; Chemical Engineering Department, University of Alcalá, Ctra. Madrid-Barcelona Km 33.600, 28871, Alcalá de Henares, Madrid, Spain.
IMDEA Water Institute, Avenida Punto Com, 2, 28805, Alcalá de Henares, Madrid, Spain.
Chemosphere. 2020 Jun;248:126027. doi: 10.1016/j.chemosphere.2020.126027. Epub 2020 Jan 30.
In this study, an activation treatment for recycled anion exchange membranes is proposed. Following the circular economy approach, these membranes were prepared by using end-of-life reverse osmosis membranes as mechanical support. The end-of-life membrane was previously used and discarded by desalination plants after overcoming its lifespan. The activation treatment was based on the subsequent immersion of the membranes in diluted acid and alkali solutions. This treatment promoted the complete dissociation of the functional groups in the membrane, making them more reactive to the counter ions. The effects of acid and alkali concentrations and exposition times on the electrochemical properties were studied and the best combination was selected. In such a way, a decrease of 37% in membrane electrical resistance was achieved. The performance of activated and non-activated membranes in brackish water desalination by electrodialysis was compared. The results showed that the proposed activation treatment increased the flux of fresh water more than four-fold (from 1.2 to 4.9 L h·m), with a considerable reduction of energy consumption (from 5.2 to 3.0 kWh·m) and a great improvement in current efficiency (from 38% to 71%). In conclusion, this work shows a simple and low cost methodology for the improvement of the electrochemical properties of recycled electromembranes and thus, their performance in electrodialysis.
本研究提出了一种再生阴离子交换膜的活化处理方法。按照循环经济的思路，以使用寿命到期的反渗透膜为机械支撑，制备这些膜。这些寿命到期的膜在海水淡化厂使用和废弃后，即被回收。活化处理基于随后将膜浸入稀释的酸和碱溶液中。这种处理促进了膜中官能团的完全解离，使其对反离子更具反应性。研究了酸和碱浓度及暴露时间对电化学性能的影响，并选择了最佳组合。这样，膜电阻降低了 37%。比较了活化和未活化膜在电渗析脱盐过程中对苦咸水的处理性能。结果表明，所提出的活化处理使淡水通量增加了四倍多（从 1.2 增加到 4.9 L h·m），同时显著降低了能耗（从 5.2 减少到 3.0 kWh·m），并极大地提高了电流效率（从 38%增加到 71%）。总之，这项工作展示了一种简单且低成本的方法，可提高再生电膜的电化学性能，从而提高电渗析的性能。
